Dave Jones

yes you can do this. Put an opening in the roof for example and it drops the efficiency big time so you have to account for it. You can also beef up other areas if you can only reach the bare minimum on a single element.

300mm is massive, does it serve a housing estate ?

passive should really be the default for what is built. The market though wont pay the extra cost to build them though. This is where the banks could incentivise by reducing rates for well built EPCA builds. Octopus are starting by giving 5 years of no bills for houses built to their spec.

ive emailed our DNO provider to ask the question.

good. it will be clowns burning pallets etc.

what sort of price are they ? Some nice designs.

no cavity closers ? much better job to build them in as you go for airtightness later on.

will be cheaper to pile if you go over 2m. Private building control indemnity limit for us was 2m anyway which meant warranty needed an engineered solution. You will need an SE to design the footing, expect piles, steel ringbeam and no change from £30- £50k

put the level on the screen it will be miles out at the bottom surely ? photo ?

not sure about that. Has the OP actually seen a copy of the builders contract works insurance ? Do they even have any at all ? I would highly doubt it as its expensive. Get a quote for contract works for say 300k of works and you be looking at 1% minimum cost. Builder wont be doing that for free so unless they given you a copy of the policy assume it doesnt exist.

who says its a habitable room ? Attached garages for example don't count.

all BCO will want is a certificate from an approved body from the sparky proving test and passed following the pre-plaster inspection. Obviously need fans in kitchen, utilty, wc,s etc along with heat / smoke/ co2 as a minimum if needed to get signed off. Cant see not putting on a few sockects and light switches will save much to be honest.

sounds like false economy for plumb and wiring. 1st fix is fast and relatively cheap as its only cable, tube and labour. how is a sparky meant to wire a single room and leave all the wires rolled up someplace ? I'd expect to be charged more for this as its a load of hassle. Not a common sense idea.

galv nails, if you must use screws stainless steel as they will rust.

with no room stat is measured the temperature of the flow and return and modulates based on that. Assuming you have rads (undefloor works same) the TRV valve in the room with burner would click off so the other rooms would heat up and click off as normal. The woodburner having the effect of speeding it up.